Example io demo

2014-01-03T22:13:58Z

Jgreene: /* Usage Example. A/D Demo */

{{todo|InProgress(12.05.13-12:47->JG+)|Jgreene|project=oe 4,oe 5,jg,md,Review}}
This is a guide to the <code>io demo</code> C example project included in the EMAC OE SDK.

The <code>io_demo</code> project provides four examples of SOM-150ES carrier board IO: 
* An analog-to-digital converter demo.
* A counter demo.
* An input-to-output demo.
* A ring demo.

The <code>io_demo</code> project builds one executable: <code>io_demo</code>.

== Opening, Building and Uploading the Project Files ==

stub

== Usage and Behaviour ==

===Hardware Requirements===

To use the '''io demo''' program you will need the following hardware.

* An EMAC [http://www.emacinc.com/som/som150es.htm SOM-150ES] carrier board. 
* A compatible EMAC SoM for that carrier board ([http://www.emacinc.com/products/system_on_module/SoM-9260M SOM-9260M], [http://www.emacinc.com/products/system_on_module/som-9G20m SOM-9G20M] and [http://www.emacinc.com/products/system_on_module/som-9x25 SOM-9X25] are all compatible and available from EMAC). 
* A multimeter or oscilloscope. See [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Input_to_Output_Demo Usage Example. Input to Output Demo] and [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Count_Demo Usage Example. Count Demo] for details. 
* A ribbon cable just long enough to reach from GPIO Port B to GPIO Port C. See [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Input_to_Output_Demo Usage Example. Input to Output Demo] for details. 

====Know Your Carrier Board====

[[File:know_your_som_150.jpg|frame|left|SOM-150ES carrier board with GPIO, LEDs and analog IO indicated.]]
 

This is a detail of the '''HDR1 PLD & BUFFERED GPIO''' header. Pin 49 is hot. The bottom pins: 2,4,6...46,48,50; are all ground. Port A is pins 1,3,5,7,9,11,13,15. Port B is pins 17,19,21,23,25,27,29,31. Port C is pins 33,35,37,39,41,43,45,47.

[[File:gpio_header_detail.png]]

===Usage for io_demo===

Run '''io demo''' from the console. It takes no parameters.

<syntaxhighlight lang="text">
./io_demo
</syntaxhighlight>

This brings up a menu of demos. 
<syntaxhighlight lang="console">
****************************
Demo Menu

A/D Demo - a
Count Demo - c
Input to Output Demo - i
Ring Demo - r

Exit - x

Enter Selection:
</syntaxhighlight>

Now we can press '''a''', '''c''', '''i''' or '''r''' to run a demo; or '''x''' to exit.

===Usage Example. A/D Demo===

From the demo menu press '''-a'''.

<syntaxhighlight lang="text">
****************************
Demo Menu

A/D Demo - a
Count Demo - c
Input to Output Demo - i
Ring Demo - r

Exit - x

Enter Selection: a

A/D Demo
[0]=126 [1]=11B [2]=12C [3]=12B
</syntaxhighlight>

What you see there is low-level ambient signals (radio waves? astral perturbations?) being picked up by the analog-in pins 11,12,13,14. Press '''a''' a few times and watch the values change.

This is the HDR8 ANALOG IO header.

[[File:analog_io_header_detail.jpg]]

Now we will play with the analog signals being picked up on our four pins.

===Usage Example. Count Demo===

From the demo menu press '''c'''.

The system counts from 0 to 255 in binary. It takes about 15 seconds to complete. 
The steps of this process are reflected in the GPIO PortC header pins (see [http://wikidev.emacinc.com/wiki/Example_io_demo#Know_Your_Carrier_Board Know Your Carrier Board], above). As each bit in our 8bit register is set to 1, the corresponding pin in the PortC header momentarily registers 5 volts (easily detected with a multimeter or oscilloscope).

More visibly, the counting process is also reflected in the strip of 8 LEDs on the board (LD1-LD8. see [http://wikidev.emacinc.com/wiki/Example_io_demo#Know_Your_Carrier_Board Know Your Carrier Board], above). A lit LED indicates a 1 in our 8 bit register and an unlit LED indicates a 0. When the counting process is finished all 8 LEDs are lit (255).

===Usage Example. Input to Output Demo===

In this usage example the carrier board talks to itself. We send an 8bit data stream directly from Port B to Port C via a short piece of ribbon cable.

<detail of board. gpio header closeup with ports b and c labelled>

This is the ribbon cable that we made for our input-to-output demo. Note that we connect PortC:pin0 to PortB:pin0; PortC:pin1 to PortB:pin1; etc. 
[[File:iodemo_homemaderibboncable.jpg|500px|border|]]

Here's our cable plugged into the GPIO header. You see that PortC:pin0 outputs to PortB:pin0; PortC:pin1 outputs to PortB:pin1; etc.
[[File:iodemo_homemaderibboncable_closeup.jpg|500px|border|]]

Our data stream for each pin is 1,0,1,0,1,0... That is to say: all pins are set to 1, then they are all set to 0, then to 1 again, etc. We observe our data stream in the strip of 8 LEDs on the carrier board. They blink in unison.

'''Note''' The blinking may get a little out of synch after a few seconds. This is normal.

===Usage Example. Ring Demo===

Refer to the SOM-150ES carrier board surface mount LEDs LD1-LD8 for output.

[[File:Io demo led action sample 2.png | 500px]]

The board lights the LEDs in numeric sequence, 1-8, then repeats; looping until a key is pressed.

Example io demo

2014-01-03T21:40:28Z

Jgreene: /* Usage Example. A/D Demo */

{{todo|InProgress(12.05.13-12:47->JG+)|Jgreene|project=oe 4,oe 5,jg,md,Review}}
This is a guide to the <code>io demo</code> C example project included in the EMAC OE SDK.

The <code>io_demo</code> project provides four examples of SOM-150ES carrier board IO: 
* An analog-to-digital converter demo.
* A counter demo.
* An input-to-output demo.
* A ring demo.

The <code>io_demo</code> project builds one executable: <code>io_demo</code>.

== Opening, Building and Uploading the Project Files ==

stub

== Usage and Behaviour ==

===Hardware Requirements===

To use the '''io demo''' program you will need the following hardware.

* An EMAC [http://www.emacinc.com/som/som150es.htm SOM-150ES] carrier board. 
* A compatible EMAC SoM for that carrier board ([http://www.emacinc.com/products/system_on_module/SoM-9260M SOM-9260M], [http://www.emacinc.com/products/system_on_module/som-9G20m SOM-9G20M] and [http://www.emacinc.com/products/system_on_module/som-9x25 SOM-9X25] are all compatible and available from EMAC). 
* A multimeter or oscilloscope. See [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Input_to_Output_Demo Usage Example. Input to Output Demo] and [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Count_Demo Usage Example. Count Demo] for details. 
* A ribbon cable just long enough to reach from GPIO Port B to GPIO Port C. See [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Input_to_Output_Demo Usage Example. Input to Output Demo] for details. 

====Know Your Carrier Board====

[[File:know_your_som_150.jpg|frame|left|SOM-150ES carrier board with GPIO, LEDs and analog IO indicated.]]
 

This is a detail of the '''HDR1 PLD & BUFFERED GPIO''' header. Pin 49 is hot. The bottom pins: 2,4,6...46,48,50; are all ground. Port A is pins 1,3,5,7,9,11,13,15. Port B is pins 17,19,21,23,25,27,29,31. Port C is pins 33,35,37,39,41,43,45,47.

[[File:gpio_header_detail.png]]

===Usage for io_demo===

Run '''io demo''' from the console. It takes no parameters.

<syntaxhighlight lang="text">
./io_demo
</syntaxhighlight>

This brings up a menu of demos. 
<syntaxhighlight lang="console">
****************************
Demo Menu

A/D Demo - a
Count Demo - c
Input to Output Demo - i
Ring Demo - r

Exit - x

Enter Selection:
</syntaxhighlight>

Now we can press '''a''', '''c''', '''i''' or '''r''' to run a demo; or '''x''' to exit.

===Usage Example. A/D Demo===

From the demo menu press '''-a'''.

<syntaxhighlight lang="text">
****************************
Demo Menu

A/D Demo - a
Count Demo - c
Input to Output Demo - i
Ring Demo - r

Exit - x

Enter Selection: a

A/D Demo
[0]=126 [1]=11B [2]=12C [3]=12B
</syntaxhighlight>

What you see there is lowish ambient signals (radio waves? spirits?) being picked up by the analog-in pins 11,12,13,14.

This is the HDR8 ANALOG IO header.

===Usage Example. Count Demo===

From the demo menu press '''c'''.

The system counts from 0 to 255 in binary. It takes about 15 seconds to complete. 
The steps of this process are reflected in the GPIO PortC header pins (see [http://wikidev.emacinc.com/wiki/Example_io_demo#Know_Your_Carrier_Board Know Your Carrier Board], above). As each bit in our 8bit register is set to 1, the corresponding pin in the PortC header momentarily registers 5 volts (easily detected with a multimeter or oscilloscope).

More visibly, the counting process is also reflected in the strip of 8 LEDs on the board (LD1-LD8. see [http://wikidev.emacinc.com/wiki/Example_io_demo#Know_Your_Carrier_Board Know Your Carrier Board], above). A lit LED indicates a 1 in our 8 bit register and an unlit LED indicates a 0. When the counting process is finished all 8 LEDs are lit (255).

===Usage Example. Input to Output Demo===

In this usage example the carrier board talks to itself. We send an 8bit data stream directly from Port B to Port C via a short piece of ribbon cable.

<detail of board. gpio header closeup with ports b and c labelled>

This is the ribbon cable that we made for our input-to-output demo. Note that we connect PortC:pin0 to PortB:pin0; PortC:pin1 to PortB:pin1; etc. 
[[File:iodemo_homemaderibboncable.jpg|500px|border|]]

Here's our cable plugged into the GPIO header. You see that PortC:pin0 outputs to PortB:pin0; PortC:pin1 outputs to PortB:pin1; etc.
[[File:iodemo_homemaderibboncable_closeup.jpg|500px|border|]]

Our data stream for each pin is 1,0,1,0,1,0... That is to say: all pins are set to 1, then they are all set to 0, then to 1 again, etc. We observe our data stream in the strip of 8 LEDs on the carrier board. They blink in unison.

'''Note''' The blinking may get a little out of synch after a few seconds. This is normal.

===Usage Example. Ring Demo===

Refer to the SOM-150ES carrier board surface mount LEDs LD1-LD8 for output.

[[File:Io demo led action sample 2.png | 500px]]

The board lights the LEDs in numeric sequence, 1-8, then repeats; looping until a key is pressed.

Example io demo

2014-01-03T21:39:51Z

Jgreene: /* Usage Example. A/D Demo */

{{todo|InProgress(12.05.13-12:47->JG+)|Jgreene|project=oe 4,oe 5,jg,md,Review}}
This is a guide to the <code>io demo</code> C example project included in the EMAC OE SDK.

The <code>io_demo</code> project provides four examples of SOM-150ES carrier board IO: 
* An analog-to-digital converter demo.
* A counter demo.
* An input-to-output demo.
* A ring demo.

The <code>io_demo</code> project builds one executable: <code>io_demo</code>.

== Opening, Building and Uploading the Project Files ==

stub

== Usage and Behaviour ==

===Hardware Requirements===

To use the '''io demo''' program you will need the following hardware.

* An EMAC [http://www.emacinc.com/som/som150es.htm SOM-150ES] carrier board. 
* A compatible EMAC SoM for that carrier board ([http://www.emacinc.com/products/system_on_module/SoM-9260M SOM-9260M], [http://www.emacinc.com/products/system_on_module/som-9G20m SOM-9G20M] and [http://www.emacinc.com/products/system_on_module/som-9x25 SOM-9X25] are all compatible and available from EMAC). 
* A multimeter or oscilloscope. See [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Input_to_Output_Demo Usage Example. Input to Output Demo] and [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Count_Demo Usage Example. Count Demo] for details. 
* A ribbon cable just long enough to reach from GPIO Port B to GPIO Port C. See [http://wikidev.emacinc.com/wiki/Example_io_demo#Usage_Example._Input_to_Output_Demo Usage Example. Input to Output Demo] for details. 

====Know Your Carrier Board====

[[File:know_your_som_150.jpg|frame|left|SOM-150ES carrier board with GPIO, LEDs and analog IO indicated.]]
 

This is a detail of the '''HDR1 PLD & BUFFERED GPIO''' header. Pin 49 is hot. The bottom pins: 2,4,6...46,48,50; are all ground. Port A is pins 1,3,5,7,9,11,13,15. Port B is pins 17,19,21,23,25,27,29,31. Port C is pins 33,35,37,39,41,43,45,47.

[[File:gpio_header_detail.png]]

===Usage for io_demo===

Run '''io demo''' from the console. It takes no parameters.

<syntaxhighlight lang="text">
./io_demo
</syntaxhighlight>

This brings up a menu of demos. 
<syntaxhighlight lang="console">
****************************
Demo Menu

A/D Demo - a
Count Demo - c
Input to Output Demo - i
Ring Demo - r

Exit - x

Enter Selection:
</syntaxhighlight>

Now we can press '''a''', '''c''', '''i''' or '''r''' to run a demo; or '''x''' to exit.

===Usage Example. A/D Demo===

From the demo menu press '''-a'''.

<syntaxhighlight lang="text">
****************************
Demo Menu

A/D Demo - a
Count Demo - c
Input to Output Demo - i
Ring Demo - r

Exit - x

Enter Selection: a

A/D Demo
[0]=126 [1]=11B [2]=12C [3]=12B
<syntaxhighlight lang="text">

What you see there is lowish ambient signals (radio waves? spirits?) being picked up by the analog-in pins 11,12,13,14.

This is the HDR8 ANALOG IO header.

===Usage Example. Count Demo===

From the demo menu press '''c'''.

The system counts from 0 to 255 in binary. It takes about 15 seconds to complete. 
The steps of this process are reflected in the GPIO PortC header pins (see [http://wikidev.emacinc.com/wiki/Example_io_demo#Know_Your_Carrier_Board Know Your Carrier Board], above). As each bit in our 8bit register is set to 1, the corresponding pin in the PortC header momentarily registers 5 volts (easily detected with a multimeter or oscilloscope).

More visibly, the counting process is also reflected in the strip of 8 LEDs on the board (LD1-LD8. see [http://wikidev.emacinc.com/wiki/Example_io_demo#Know_Your_Carrier_Board Know Your Carrier Board], above). A lit LED indicates a 1 in our 8 bit register and an unlit LED indicates a 0. When the counting process is finished all 8 LEDs are lit (255).

===Usage Example. Input to Output Demo===

In this usage example the carrier board talks to itself. We send an 8bit data stream directly from Port B to Port C via a short piece of ribbon cable.

<detail of board. gpio header closeup with ports b and c labelled>

This is the ribbon cable that we made for our input-to-output demo. Note that we connect PortC:pin0 to PortB:pin0; PortC:pin1 to PortB:pin1; etc. 
[[File:iodemo_homemaderibboncable.jpg|500px|border|]]

Here's our cable plugged into the GPIO header. You see that PortC:pin0 outputs to PortB:pin0; PortC:pin1 outputs to PortB:pin1; etc.
[[File:iodemo_homemaderibboncable_closeup.jpg|500px|border|]]

Our data stream for each pin is 1,0,1,0,1,0... That is to say: all pins are set to 1, then they are all set to 0, then to 1 again, etc. We observe our data stream in the strip of 8 LEDs on the carrier board. They blink in unison.

'''Note''' The blinking may get a little out of synch after a few seconds. This is normal.

===Usage Example. Ring Demo===

Refer to the SOM-150ES carrier board surface mount LEDs LD1-LD8 for output.

[[File:Io demo led action sample 2.png | 500px]]

The board lights the LEDs in numeric sequence, 1-8, then repeats; looping until a key is pressed.

2014-01-03T17:51:12Z

Jgreene: /* Using socket */

Example watchdog

2014-01-03T17:34:20Z

Jgreene: /* Usage Example. Enabling watchdog */

{{todo|Review(01.03.14-11:32->JG+)|Jgreene|project=oe 4,oe 5,jg,md,Review}}
This is a guide to the <code>watchdog</code> C example project included in the EMAC OE SDK.

A '''watchdog timer''' (WDT) is a hardware circuit that can reset the computer system in case of a software fault. This is an example test for the Linux watchdog API.

The <code>watchdog</code> project builds one executable: <code>watchdog-test</code>.

== Opening, Building and Uploading the Project Files ==

<big>stubbooo</big>

==Usage and Behavior==

A '''watchdog timer''' is a hardware circuit that can reset the computer system in case of a software fault. The <code>watchdog-test</code> application can enable, disable, activate, configure and interrupt the '''watchdog timer'''.
{{imbox|type=content|textstyle=font-weight:bold;|text= Activating watchdog invokes system reset (after timeout)}}

===Hardware Requirements===

<code>watchdog</code> will run on any system for which it can be compiled and implements the standard Linux <code>watchdog</code> API.

===<code>watchdog</code> Usage===

./watchdog-test [-det]

;-d:Disable watchdog.
;-e:Enable watchdog.
;-t:Set the watchdog timeout (to a value specified in code. Default is five seconds).

===Usage Example. Activating <code>watchdog</code> with a periodic interrupt===

This will activate <code>watchdog</code> and initiate a periodic interrupt to keep it from timing out.

<syntaxhighlight lang="text">
root@som9g20:/tmp# ./watchdog-test
Watchdog Ticking Away!
</syntaxhighlight>

We have activated <code>watchdog</code> and now it is counting down to computer reset - or rather it would be if we didn't keep resetting it's timer. That's the LED on the SoM blinking at about 1 Hz. Every second <code>watchdog-test</code> is sending an IOCTL to the watchdog driver, which in turn ticks <code>watchdog</code> to reset its internal timer so it doesn't timeout and trigger a system reset.

Now we will stop interrupting <code>watchdog</code> and let it trigger a computer reset. Hit CTRL-C.

...and the system resets.

===Usage Example. Disabling <code>watchdog</code>===

<syntaxhighlight lang="text">
root@som9g20:/tmp# ./watchdog-test -d
Watchdog card disabled.
</syntaxhighlight>

...and the program exits normally.

===Usage Example. Enabling <code>watchdog</code>===

This will enable and activate <code>watchdog</code> but it won't perform a periodic timeout interrupt (see the first usage example, above). So when you run it the program activates <code>watchdog</code> and then <code>watchdog</code> resets the system.

<syntaxhighlight lang="text">
root@som9g20:/tmp# ./watchdog-test -e
Watchdog card enabled.
</syntaxhighlight>

...and the system resets.

===Usage Example. Setting <code>watchdog</code> timeout===

This will activate <code>watchdog</code> and set it to timeout in 5 seconds.

<syntaxhighlight lang="text">
root@som9g20:/tmp# ./watchdog-test -t
Watchdog timeout set to 5 seconds!
</syntaxhighlight>

...the program exits normally, then 5 seconds elapse, and then the system resets.

==Summary==

The <code>watchdog</code> C example project demonstrates how to use the '''watchdog timer'''. We provide examples of how to enable, disable, activate, configure and interrupt the <code>watchdog</code> hardware circuit.